Four miners were killed and another was seriously injured after a colliery collapsed in Xinjiang Uygur Autonomous Region Friday, local authorities said Saturday.

A pit owned by Xinjiang Shenhua Tiandian Mining Co. Ltd. in Hutubi County in Changji Hui Autonomous Prefecture caved in at about 9 a.m. Friday when 23 miners were digging underground, according to officials with the Coal Mine Safety Supervision Administration of Xinjiang.

Eighteen miners escaped and four were found dead. The injured is in a stable condition after emergency treatment in hospital.

Pit operations have been halted and investigators of the administration are probing into the accident.

The Xinjiang-based company is a subsidiary of China Shenhua Group, the largest coal producer in the country.